8155561 has 2 divisors, whose sum is σ = 8155562. Its totient is φ = 8155560.

The previous prime is 8155531. The next prime is 8155591. The reversal of 8155561 is 1655518.

It is a balanced prime because it is at equal distance from previous prime (8155531) and next prime (8155591).

It can be written as a sum of positive squares in only one way, i.e., 8037225 + 118336 = 2835^2 + 344^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8155561 is a prime.

It is not a weakly prime, because it can be changed into another prime (8155531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4077780 + 4077781.

It is an arithmetic number, because the mean of its divisors is an integer number (4077781).

Almost surely, 2^8155561 is an apocalyptic number.

It is an amenable number.

8155561 is a deficient number, since it is larger than the sum of its proper divisors (1).

8155561 is an equidigital number, since it uses as much as digits as its factorization.

8155561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6000, while the sum is 31.

The square root of 8155561 is about 2855.7942853084. The cubic root of 8155561 is about 201.2880287689.

The spelling of 8155561 in words is "eight million, one hundred fifty-five thousand, five hundred sixty-one".